Surface treatment processes are widely used in the furniture industry in particular. The wooden materials used in that industry are not normally left in their original state, but receive a refining surface coating, generally a melamine coating. Veneers, decorative laminates or decorative films are also used as coating materials.
The coating of side faces, edges or, generally, narrow surfaces often involves the use of a special edging material, for example an edge veneer or a so-called narrow-surface band which is applied to the narrow surfaces with an adhesive. This process is generally known as edge banding.
However, it is often desirable to round off the narrow surfaces or edges for aesthetic reasons or to provide profiled surfaces for functional reasons. Besides the edge banding process mentioned above, which is also known as soft-forming, other processes are used to coat the "soft" contours in question.
One way of carrying out surface coating is to use the coating material on top and underneath as the edging material. In a first step, the coating material is applied to the upper and lower surfaces of a board to be coated, preferably using a dispersion adhesive. A sufficient excess length of the coating material is generally left in the vicinity of the edge to be coated and is suitably flexibilized, normally by heating. The flexibilized excess length is then bent around the edge to be coated and secured with a dispersion or hotmelt adhesive. This process is also known as post-forming.
In a modification of the post-forming process described above, the excess length of coating material is obtained by free milling, the material situated below the required excess length being removed. This process is known as direct post-forming.
However, one aspect common to all these processes is that they use a solid coating material which is difficult to handle and also expensive, not least because of non-reusable cutting waste.
In addition, the surfaces to be coated are often extremely uneven with voids, etc. This applies in particular to chipboards.
Surfaces in this condition coated by one of the processes mentioned above lead to a very uneven, "bumpy", wavy material surface which spoils the appearance of, for example, the subsequent piece of furniture. To produce an improvement, thicker edging or coating materials are often used. They are capable of satisfactorily levelling out the surface unevenness and of preventing the surface substrate from showing through (telegraphing). Unfortunately, any increase in the thickness of the coating material is accompanied by an increase in the stiffness of the bent coating material. This in turn leads to an increased press-on length for gluing the stiffer coating material. Moreover, stiffer coating materials are generally more expensive.
These disadvantages cannot be eliminated in the described post-forming processes either.
Accordingly, the problem addressed by the present invention was to provide a process and an arrangement with which the disadvantages mentioned above could be eliminated and a surface smoothing treatment could readily be carried out.